Communication schemes such as Wideband Code Division Multiple Access (W-CDMA) are used as third generation mobile communication systems. In the W-CDMA scheme, for example, a transmission and reception frequency interval in a 2 GHz frequency band is fixed to 190 MHz. When a frequency in a downlink band in which a wireless communication device performs reception is determined, a frequency in an uplink band in which a terminal performs transmission is also determined accordingly. That is, in the W-CDMA scheme, communication is performed in which the frequency in the downlink band that is used and the frequency in the uplink band are stipulated in a one-to-one correspondence manner.
On the other hand, it is desirable that with a recent increase in the amount of information data that is communicated by a user, communication throughput is improved. As one solution of improving the communication throughput, it is considered that the wireless communication device is caused to perform communication in multiple frequency bands at the same time to secure a bandwidth for communication. As a technology of performing communication in multiple frequency bands at the same time, there is carrier aggregation. The carrier aggregation is hereinafter referred to as a CA. In the CA, for example, multiple component carriers, a bandwidth of each being 20 MHz, are integrated and thus communication is performed. Thus, a bandwidth that is as broad as 60 MHz is secured, and high-speed, high-capacity communication is realized.
In regard to this, technologies are known in which, when multiple mobile communication systems are present in a mixed manner, a mobile terminal device and a wireless base station device are provided that correspond to each of the multiple mobile communication systems (for example, Japanese Laid-open Patent Publication No. 2010-74754). On the other hand, technologies relating to the wireless communication device are disclosed in Japanese Laid-open Patent Publication No. 2002-118428, Japanese Laid-open Patent Publication No. 7-170204, Japanese Examined Utility Model Application Publication No. 1-034442, Japanese Laid-open Patent Publication No. 2009-124746, and Japanese Laid-open Patent Publication No. 2000-156607.
However, for example, in the case where the wireless communication device performs communication in multiple frequency bands at the same time, such as when the CS is performed, among multiple antennas that are included in the wireless communication device, a transmission wave from a certain antenna causes the frequency interference to occur in a reception band for communication through another antenna. For this reason, communication performance deteriorates in the wireless communication device that performs communication in multiple frequency bands at the same time.